The Great Turtle-Egg Evacuation

Posted by Alex H.

The Deepwater Horizon oil spill is a very, very sad story. No matter how you look at it, the whole thing is spelling disaster.

What is surprising to me is how the event is being labeled as an ecological disaster by the mainstream media. Even though the explosion of the oil platform has left 11 dead (plus 2) and 17 injured, these facts have been essentially forgotten as the yet-contained oil continues to spew into the Gulf of Mexico and its surrounding shoreline. The focus is not unwarranted in most respects, as the consequences of this input of crude into the Gulf and associated cleanup efforts have and will have staggering effects on the ecology of the Gulf of Mexico and the Atlantic Ocean.

Unsurprisingly, an already-struggling effort for effective sea turtle conservation is being hit with very difficult decisions about what to do. Several species of adult sea turtles are running the risk of being cremated alive when caught inside oil slicks being burned. Additionally, as eggs hatch from nests on the beaches of the Gulf, juvenile turtles would face thousands of miles of oil-polluted water in the most vulnerable time of a sea turtle's life.

This last situation is why the US Fish and Wildlife Service, the National Marine Fisheries Service, and the Florida Marine Fisheries Service have developed a plan to relocate an estimated 70,000 sea turtle eggs from almost 800 beaches along Alabama and Florida. Read more here: The Great Turtle-Egg Evacuation

The plan is very risky for turtles inside eggs. As the article states:

"[...] within 12–24 hours of the eggs being laid, embryos attach to an oxygen-supplying membrane. So any movement of the eggs could cause detachment and death [...]."

A former student from my university completed a series of research projects on sea turtle conservation in the last few years which illuminated my perception of the effectiveness of current conservation efforts. This last point about the eggs dying if moved at the wrong point in time is correct, and is a major concern in these operations.

This topic has been a hot one in many email listservs I am subscribed to (especially C-TURTLE), and the point most interesting to me in all of this is the question of how the relocated hatched juveniles will respond to being transported to beaches several hundred miles from where they were laid. The previously-linked article continues to talk about potential affects of this operation on the relocated turtle's behavior:

Moving the eggs is not generally viewed as problematic. "We have adequate data showing that eggs moved with competence at that age have no difference in survivorship to those not moved," said Mike Salmon, a biologist at Florida Atlantic University in Boca Raton. 

But the release could be another matter. "What we don't know is what impact it might have on other aspects of behaviour," says Salmon. 

"The $64,000 question is, if you take hatchlings that would normally emerge in northwest Florida to the east coast," he said, "will they return there, or to the northwest, where they should go?" Because scientists don't know for sure whether imprinting occurs in the nest or after emergence, this remains a mystery.

This point is one where conservation, ecology, and ethology intersect. My favorite! I anticipate some interesting research will come out of this project, especially if local behavioral research-heavy universities (e.g., University of Florida) are asked to become involved. So much is known about sea turtle navigation and spatial perception, but I do not know of any test which has analyzed how moving recently hatched eggs 500 miles away affects the survival of individuals. Normally, this is not a practical situation which would not require testing (and thus, I see why there is a paucity of research on this specific topic).

Finally, it is worth noting that Heppell et al. (1996) found that the most effective contributors to sea turtle conservation were not efforts directed towards very young sea turtle (particularly 'headstarting', or catching recently hatched individuals and raising them for a year before release). Instead, turtle excluder devices (TEDs) attached to shrimp trawling nets offer the greatest positive effect on their survival. I wonder how meaningful this project to move ~70,000 eggs will be in light of these results.

Thank you for reading, I hope you are doing your part to support relief and clean-up efforts in the wake of this ecologically-disruptive event.

Addendum: I could insert lots of opinion on the oil spill, but I'll pass for two reasons: 1) I'm not a geologist, and 2) no one wants to read my whining (not even me). You can read more about sea turtle headstarting here.